In scrap, price per kilogram gets all the attention, but weight is just as important. A 2% weight error on a 20-tonne truck of MS scrap is 400 kg. On copper, even a few kilograms matters. Weighbridges, known across north India as dharm kata, are the backbone of fair scrap trading. This guide explains how weighbridge weighing works and how to protect yourself from errors and fraud.
How weighbridge weighing works
A weighbridge is a large platform scale that weighs entire vehicles. For scrap:
- Tare weight: The empty truck is weighed before loading.
- Gross weight: The loaded truck is weighed after loading.
- Net weight: Gross minus tare equals the weight of the scrap.
Both weighings should take place on the same weighbridge, on the same day where possible, with the same driver and vehicle condition.
What makes a weighbridge trustworthy
- Legal metrology verification: Weighbridges used for trade must be verified and stamped by the Legal Metrology department at prescribed intervals. Ask to see the current verification certificate.
- Printed slips: Computerised slips showing vehicle number, date, time, tare, gross, net and a serial number.
- Visible display: Both parties should see the reading.
- Level, clean platform: Debris, water or a vehicle not fully on the platform affects readings.
- Independent operator: Public or third-party weighbridges reduce conflicts of interest.
Common weight manipulation tricks
Knowing the tricks helps you spot them:
At tare (empty) weighing
- Extra people in the cabin who leave before gross weighing.
- Water tanks or extra fuel that is drained before gross weighing.
- Heavy tools, spare tyres or chains in the truck that are removed later.
These inflate the tare, reducing calculated net weight and under-paying the seller.
At gross (loaded) weighing
- Water poured on scrap to add weight (cheating the buyer).
- Soil or concrete mixed into the load.
- Hidden heavy objects.
At the platform
- Vehicle wheels partly off the platform.
- Someone leaning on or standing at the edge.
- Using a different truck number for tare and gross.
Documentary tricks
- Fake or altered slips.
- Slips from a weighbridge that does not exist.
- Mismatched times showing gross before tare.
Best practices for sellers
- Agree the weighbridge in advance, in writing.
- Witness both weighings, or send a trusted representative.
- Check the cabin and truck before tare: count people, note spare tyres and tools.
- Photograph the truck on the platform at both weighings, with the display visible.
- Check the vehicle number on slips matches the truck.
- Check timestamps: Tare before gross, reasonable time gap for loading.
- Keep original slips and share copies with your accounts team.
- Compare with estimates: Large deviations from expected weight need explanation.
Best practices for buyers
- Weigh incoming trucks on your own calibrated weighbridge and compare with dispatch slips.
- Inspect loads for water, soil and hidden items.
- Agree tolerance limits for dispatch vs receipt weight differences.
- Maintain records of supplier weight performance.
Handling weight differences
Some difference between dispatch and receipt weights is normal: different weighbridges have small tolerances, and moisture can evaporate. Agree a tolerance in your contract, commonly a small fraction of a percent to around half a percent depending on material and distance. Larger, consistent differences require investigation.
Platform scales for high-value metals
For copper, brass and other high-value non-ferrous metals sold in smaller quantities, weigh on a calibrated platform scale:
- Check the scale's verification stamp.
- Zero the scale in front of both parties.
- Weigh in bags or crates, recording each weighing.
- Subtract bag or crate weights consistently.
Deductions vs weight
Weight disputes are often mixed up with deductions. Keep them separate:
- Weight is what the weighbridge measures.
- Deductions are agreed reductions for contamination, moisture or attachments.
Deductions should be agreed before loading, calculated transparently and recorded separately on the invoice or settlement.
Digital records
Modern weighbridges can send slips digitally, with photos from cameras mounted at the platform. These records reduce disputes. Ask whether your weighbridge provides camera images and digital slips.
Why location matters
Choosing a well-known, independent weighbridge near the loading site saves time and reduces opportunities for manipulation in transit. In Ramnagar, Varanasi, Kabadi24's head office is directly opposite Swastik Dharm Kata on Main Road, Industrial Area Phase 1, which makes weighment quick and transparent for units in the area.
A worked example: spotting a tare problem
A seller ships two trucks of MS scrap on the same day with the same transporter. Slips show:
| Truck | Tare | Gross | Net |
|---|---|---|---|
| Truck 1 | 9,840 kg | 26,120 kg | 16,280 kg |
| Truck 2 | 10,620 kg | 26,080 kg | 15,460 kg |
Both trucks are the same model, so tare weights should be close. Truck 2's tare is 780 kg higher. On checking photos, the seller sees two extra people and a full water drum in Truck 2's cabin at tare weighing. That inflated tare cost the seller about 780 kg of scrap on one truck. The issue is resolved by re-weighing Truck 2 empty after unloading, and the seller's process is updated to photograph the cabin at every tare weighing.
Weighment checklist for every truck
- Agreed weighbridge with valid verification.
- Truck number checked and photographed.
- Cabin and body checked before tare: people, tools, water, spare tyres.
- Tare slip collected with time.
- Loading supervised.
- Gross weighing with all wheels on platform; display photographed.
- Gross slip collected; net calculated and checked.
- Slips attached to gate pass and invoice.
Weighbridge vs platform scale: when to use which
| Situation | Best option |
|---|---|
| Truck loads of ferrous scrap | Weighbridge |
| Mixed truck with several grades | Weighbridge per grade or sequential weighing |
| Copper, brass, aluminium under 2–3 tonnes | Calibrated platform scale, bag by bag |
| Batteries and e-waste | Platform scale with item counts |
| Machines sold as whole units | Weighbridge before and after loading |
Weighbridge glossary
- Tare: Weight of the empty vehicle.
- Gross: Weight of the loaded vehicle.
- Net: Gross minus tare; the weight you are paid for.
- Verification / stamping: Periodic certification of the weighbridge by the Legal Metrology department.
- Tolerance: The acceptable difference between two weighments, agreed in the contract.
- Kata parchi: The printed weighbridge slip.
- Deduction: An agreed reduction for contamination or moisture, separate from weight.
Small habits that prevent big losses
Ask the driver to step out of the cabin during both weighings, keep the same driver for tare and gross, weigh tare just before loading rather than the previous day, and photograph the fuel gauge if the truck will refuel between weighings. None of these steps takes more than a minute, yet together they close most of the common loopholes. For regular dispatches, keep a simple log of each vehicle's usual tare so unusual readings stand out immediately.
What to do if you suspect a wrong weight
Do not argue at the weighbridge without evidence. Note the readings, take photos, and ask for the vehicle to be reweighed empty after unloading. Compare with previous trips by the same truck and with your own estimate of the load. If the difference is confirmed, settle on the corrected weight in writing before releasing payment or signing the invoice. For repeated problems, change the weighbridge or the transporter, and add a weight tolerance clause to future contracts. A calm, evidence-based approach resolves most disputes quickly and preserves the business relationship.
How Kabadi24 handles weighment
Every truck lot traded through Kabadi24 is weighed at a certified weighbridge with tare and gross slips shared with both parties. For high-value non-ferrous metals, we use calibrated platform scales in front of the seller. On marketplace deals across India, dispatch and receipt weights are reconciled against agreed tolerances.
Conclusion
Fair weight is as important as fair price. Use verified weighbridges, witness both weighings, check slips carefully, keep photos, and agree deductions separately. These habits protect both sellers and buyers and build long-term trust.